hello everyone! ive got an an accordion which is a royal standard montana 120 bass. it is quite old, i think it is from the 70s but in great condition, hardly ever used. it works but like 2-3 keys arent pushing down properly(they kind of get stuck when you bottom them out) so obviously the accordion needs some repairs. it also has its original case and so on. i would like to sell it and i do not know how much can i get for it. if anyone here can help me out i would really appreciate it!!